TAIPEI (Taiwan News) — Taiwan’s Taichung Minquan Road Post Office discovered Thursday (Sept. 5) it had mistakenly made duplicate salary payments to over 10,000 employees.

The total overpayment amounted to NT$380 million (US$12 million). Employees were notified to return the excess funds, per CNA.

As of 10 a.m. Saturday (Sept. 7), there were still 12 transactions that had not been corrected. These transactions totaled over NT$400,000.

Wang Yueh-chen (王月珍), acting director of the post office, explained that salary transfers must be reviewed by a supervisor. An employee initiated the transfer process on Tuesday (Sept. 3) but mistakenly believed the file had been deleted.

The employee re-initiated the transfer on Wednesday (Sept. 4). Supervisors who reviewed the two transfers were different individuals, and failed to notice salary duplications.

Wang said that some employees withdrew the extra money before the post office could fix the mistake. The post office had to contact these employees directly.

If the funds are not returned, they will reportedly take them out of future paychecks. The post office pledged to strengthen employee training to prevent similar incidents.